In “On the Move,” our regular column about migration, we present pairs of distribution maps from eBird that you can use to compare where interesting birds are at different times of year. We featured Mountain Bluebird, pictured above, and Hudsonian Godwit in our April 2015 issue.
A sign of spring across much of the western United States is the return of Mountain Bluebird, a dainty blue thrush of open country. These eBird maps compare its distribution between January and April 2004-2014. The map at left shows the bird’s nonbreeding distribution across much of the southwestern states and locally in northern Mexico. In winter, birders should look for the species in open habitats such as oak savannah and grasslands; be aware that it can often be found with other bluebird species. By April, Mountain Bluebird has returned to much of the western U.S., as well as western Canada and locally to southeastern Alaska. Favored breeding habitats include meadows and other open areas above 5,000 feet in elevation. Purple squares in central Illinois, northwestern Ohio, western Massachusetts, and other places represent very rare eastern records.
The maps above show the distribution of Hudsonian Godwit in January and April, from 2004 to 2014. For about half of each year, it inhabits coastal lagoons and mudflats in a few core areas in southern South America, which are represented by dark purple squares on the map at left. The main wintering areas are in just three locations: Isla Chiloé in Chile, near Buenos Aires, and in Tierra del Fuego. By April, most godwits from Isla Chiloé are on their way to Alaska. They stop over in the Great Plains, where birders should look for them in bodies of shallow water from the Gulf coast of Texas to Alberta. Purple squares on the map represent sightings along this narrow longitudinal corridor. Populations from Buenos Aires and Tierra del Fuego migrate through the Great Plains a month later, in May, and ultimately reach breeding areas along southern Hudson Bay in Canada.
eBird is the real-time online checklist operated by the Cornell Lab of Ornithology and Audubon. “On the Move” is written by eBird’s Garrett MacDonald, Chris Wood, Marshall Iliff, and Brian Sullivan. Submit your bird sightings at ebird.org.
A version of this article appeared in “Birding Briefs” in the April 2015 issue of BirdWatching. Subscribe.Originally Published